/*
 * ppp-comp.h - Definitions for doing PPP packet compression.
 *
 * Copyright 2000 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 1994 The Australian National University.
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation is hereby granted, provided that the above copyright
 * notice appears in all copies.  This software is provided without any
 * warranty, express or implied. The Australian National University
 * makes no representations about the suitability of this software for
 * any purpose.
 *
 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
 * THE AUSTRALIAN NATIONAL UNIVERSITY HAVE BEEN ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
 * OR MODIFICATIONS.
 *
 * $Id: ppp-comp.h,v 1.11 1998/03/25 03:33:34 paulus Exp $
 */

#ifndef _NET_PPP_COMP_H
#define	_NET_PPP_COMP_H

#ifdef __cplusplus
extern "C" {
#endif

/*
 * The following symbols control whether we include code for
 * various compression methods.
 */
#ifndef DO_BSD_COMPRESS
#define	DO_BSD_COMPRESS	1	/* by default, include BSD-Compress */
#endif
#ifndef DO_DEFLATE
#define	DO_DEFLATE	1	/* by default, include Deflate */
#endif
#define	DO_PREDICTOR_1	0
#define	DO_PREDICTOR_2	0

/*
 * Structure giving methods for compression/decompression.
 */
#ifdef PACKETPTR
struct compressor {
	int	compress_proto;	/* CCP compression protocol number */

	/* Allocate space for a compressor (transmit side) */
	void	*(*comp_alloc) __P((uchar_t *options, int opt_len));
	/* Free space used by a compressor */
	void	(*comp_free) __P((void *state));
	/* Initialize a compressor */
	int	(*comp_init) __P((void *state, uchar_t *options, int opt_len,
	    int unit, int hdrlen, int debug));
	/* Reset a compressor */
	void	(*comp_reset) __P((void *state));
	/* Compress a packet */
	int	(*compress) __P((void *state, PACKETPTR *mret,
	    PACKETPTR mp, int orig_len, int max_len));
	/* Return compression statistics */
	void	(*comp_stat) __P((void *state, struct compstat *stats));

	/* Allocate space for a decompressor (receive side) */
	void	*(*decomp_alloc) __P((uchar_t *options, int opt_len));
	/* Free space used by a decompressor */
	void	(*decomp_free) __P((void *state));
	/* Initialize a decompressor */
	int	(*decomp_init) __P((void *state, uchar_t *options, int opt_len,
				    int unit, int hdrlen, int mru, int debug));
	/* Reset a decompressor */
	void	(*decomp_reset) __P((void *state));
	/* Decompress a packet. */
	int	(*decompress) __P((void *state, PACKETPTR *mp));
	/* Update state for an incompressible packet received */
	int	(*incomp) __P((void *state, PACKETPTR mp));
	/* Return decompression statistics */
	void	(*decomp_stat) __P((void *state, struct compstat *stats));

	/* Set or change compression effort level */
	int	(*set_effort) __P((void *xstate, void *rstate,
	    int effortlevel));
};
#endif /* PACKETPTR */

/*
 * Return values for decompress routine.
 * We need to make these distinctions so that we can disable certain
 * useful functionality, namely sending a CCP reset-request as a result
 * of an error detected after decompression.  This is to avoid infringing
 * a patent held by Motorola.
 * Don't you just lurve software patents.
 */
#define	DECOMP_OK		0	/* everything went OK */
#define	DECOMP_ERROR		1	/* error detected before decomp. */
#define	DECOMP_FATALERROR	2	/* error detected after decomp. */

/*
 * CCP codes.
 */
#define	CCP_CONFREQ	1
#define	CCP_CONFACK	2
#define	CCP_TERMREQ	5
#define	CCP_TERMACK	6
#define	CCP_RESETREQ	14
#define	CCP_RESETACK	15

/*
 * Max # bytes for a CCP option
 */
#define	CCP_MAX_OPTION_LENGTH	32

/*
 * Parts of a CCP packet.
 */
#define	CCP_CODE(dp)		((dp)[0])
#define	CCP_ID(dp)		((dp)[1])
#define	CCP_LENGTH(dp)		(((dp)[2] << 8) + (dp)[3])
#define	CCP_HDRLEN		4

#define	CCP_OPT_CODE(dp)	((dp)[0])
#define	CCP_OPT_LENGTH(dp)	((dp)[1])
#define	CCP_OPT_MINLEN		2

/*
 * Definitions for BSD-Compress.
 */
#define	CI_BSD_COMPRESS		21	/* config. option for BSD-Compress */
#define	CILEN_BSD_COMPRESS	3	/* length of config. option */

/* Macros for handling the 3rd byte of the BSD-Compress config option. */
#define	BSD_NBITS(x)		((x) & 0x1F)	/* number of bits requested */
#define	BSD_VERSION(x)		((x) >> 5)	/* version of option format */
#define	BSD_CURRENT_VERSION	1		/* current version number */
#define	BSD_MAKE_OPT(v, n)	(((v) << 5) | (n))

#define	BSD_MIN_BITS		9	/* smallest code size supported */
#define	BSD_MAX_BITS		15	/* largest code size supported */

/*
 * Definitions for Deflate.
 */
#define	CI_DEFLATE		26	/* config option for Deflate */
#define	CI_DEFLATE_DRAFT	24	/* value used in original draft RFC */
#define	CILEN_DEFLATE		4	/* length of its config option */

#define	DEFLATE_MIN_SIZE	8
#define	DEFLATE_MAX_SIZE	15
#define	DEFLATE_METHOD_VAL	8
#define	DEFLATE_SIZE(x)		(((x) >> 4) + DEFLATE_MIN_SIZE)
#define	DEFLATE_METHOD(x)	((x) & 0x0F)
#define	DEFLATE_MAKE_OPT(w)	((((w) - DEFLATE_MIN_SIZE) << 4) \
				    + DEFLATE_METHOD_VAL)
#define	DEFLATE_CHK_SEQUENCE	0

/*
 * Definitions for other, as yet unsupported, compression methods.
 */
#define	CI_PREDICTOR_1		1	/* config option for Predictor-1 */
#define	CILEN_PREDICTOR_1	2	/* length of its config option */
#define	CI_PREDICTOR_2		2	/* config option for Predictor-2 */
#define	CILEN_PREDICTOR_2	2	/* length of its config option */

/*
 * Note that some systems emit requests for STAC using a length of 6.
 * The extra octet is 00 and should be ignored.
 */
#define	CI_STAC			17	/* config option for STAC LZS */
#define	CILEN_STAC		5	/* length of its config option */

#define	STAC_CHK_NONE		0	/* No checking */
#define	STAC_CHK_LCB		1	/* Longitudinal Check Bytes */
#define	STAC_CHK_CRC		2	/* Cyclic Redundancy Check */
#define	STAC_CHK_SEQ		3	/* Sequence Number */
#define	STAC_CHK_EXTENDED	4	/* Extended (Microsoft) */

#define	CI_MPPC			18	/* config option for MS-PPC */
#define	CILEN_MPPC		6	/* length of its config option */

#define	MPPC_COMP		0x00000001	/* Compression */
#define	MPPC_40LANM		0x00000010	/* MPPE, 40 bit LANManager */
#define	MPPC_40NT		0x00000020	/* MPPE, 40 bit NT key */
#define	MPPC_128NT		0x00000040	/* MPPE, 128 bit NT key */
#define	MPPC_56NT		0x00000080	/* MPPE, 56 bit NT key */
#define	MPPC_PBP		0x01000000	/* Packet-by-Packet mode */
#define	MPPC_MPPE		0x000000F0

#ifdef __cplusplus
}
#endif

#endif /* _NET_PPP_COMP_H */
